Driver/Darwin: Be bug compatible with GCC and ignore -pg on ARM.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126767 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 561476e..4a9be0e 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -918,6 +918,11 @@
   return 0;
 }
 
+bool Darwin::SupportsProfiling() const {
+  // Profiling instrumentation is only supported on x86.
+  return getArchName() == "i386" || getArchName() == "x86_64";
+}
+
 bool Darwin::SupportsObjCGC() const {
   // Garbage collection is supported everywhere except on iPhone OS.
   return !isTargetIPhoneOS();